The Role of Gut Microbiota-Derived Butyrate in Inflammation and Neurological Outcomes after Neonatal Hypoxic-Ischemic Encephalopathy

Neonatal hypoxic-ischemic encephalopathy (nHIE) is a leading cause of pediatric neurodevelopmental disabilities worldwide. Therapeutic hypothermia, the only treatment, must be initiated within six hours of birth, is limited to specialized centers, and primarily targets acute inflammation. Chronic inflammation, driven by T- lymphocytes in the periphery and microglia in the brain, persists for years, hindering brain development. Targeting chronic inflammation presents a unique opportunity to improve long-term nHIE outcomes. The gut microbiota plays a critical role in shaping the immune system, with its metabolites like butyrate promoting anti-inflammatory immune responses. My preliminary studies using the Rice-Vannucci model of nHIE showed a significant decline in short-chain fatty acid-producing bacteria, including butyrate producers, which persisted for 5 months post-injury. Butyrate is lower in the stool and brain of mice with brain injury compared to controls, suggesting that chronic butyrate deficiency may drive persistent inflammation. Fecal microbiota transplantation (FMT) from healthy mice reversed anxiety and hyperactivity in nHIE mice, while FMT from nHIE mice induced depressive behavior in naïve recipients. I will define how gut microbiota-derived butyrate modulates both peripheral and central inflammation, enhancing regulatory T cell maturation and promoting an anti-inflammatory microglial polarization, ultimately improving long- term outcomes after nHIE. In Aim 1: I will determine how chronic gut microbiota alterations following nHIE affect neurological outcomes. We will use FMT and shotgun metagenomics to assess microbial changes and correlate butyrate levels with behavioral outcomes. In Aim 2, I will analyze how butyrate modulates peripheral inflammation by promoting Treg maturation. We will combine FMT, butyrate administration, and Treg depletion (using DEREG mice) to assess systemic inflammatory responses. In Aim 3, I will determine how butyrate influences central inflammation and microglial activation. We will use butyrate treatment and microglia depletion (in Tmem119-DTR mice) to assess microglial phenotypes and inflammatory markers in the brain, correlating these with outcomes. This K08 award will close key knowledge gaps in 1) integrative analysis of the gut-brain axis, 2) immune modulation in brain injury, and 3) laboratory team leadership skills. These short-term goals will equip me to integrate microbiota, immune, and brain research into an independent program aimed at developing novel treatment strategies for nHIE. Project Number: 1K08HD120866-01 | Fiscal Year: 2026 | NIH Institute/Center: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) | Principal Investigator: Viola Caretti | Institution: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON, HOUSTON, TX | Award Amount: $162,000 | Activity Code: K08 | Study Section: Special Emphasis Panel[ZRG1 CN-F (91)] View on NIH RePORTER: https://reporter.nih.gov/project-details/1K08HD12086601